1. Field of the Invention
The present invention relates to matrix type displays, and more particularly to a matrix display having a flat panel display element such as a liquid crystal panel or electroluminescent panel driven by non-interfering optically communicated signals.
2. Description of the Related Art
A flexible substrate such as a tape carrier package is frequently used for electrical connection between a liquid crystal panel and a substrate for external circuits of a matrix type liquid crystal display. When the liquid crystal panel and the substrate are electrically connected by the flexible substrate, the liquid crystal panel and the flexible substrate must be electrically connected, as well as the flexible substrate and the substrate for external circuits, thereby increasing the complexity of the assembly process and the cost of the resulting display.
Liquid crystal displays including that disclosed in Japanese unexamined patent publication No. Hei. 8-16131 have been proposed in view of the above drawbacks by transmitting signals between a liquid crystal panel and a substrate for external circuits using light. As a result, the above electrical connections can be eliminated, thereby significantly reducing the cost of a liquid crystal display.
However, recent trends require liquid crystal panels having larger screens (higher definition) and greater amounts of displayed information, thereby necessitating an increase in the current signal transmission capacity for XGA (1024xc3x97768 dots) and SXGA (1280xc3x971024 dots) standards to a value that can support full color display according to UXGA (1600xc3x971200 dots) standard. As a result, high-density transmission-reception pairs will be required not only for signal transmission based on electrical connection but also for the transmission of optical signals. The apparatus disclosed in the above-cited publication may exhibit certain limitations when it has a high density transmission-reception pair configuration, as no consideration is paid to signal interference between adjacent signal transmission paths.
It is therefore an object of the invention to provide an active matrix type display in which information is optically transmitted to a flat panel display element, such as a liquid crystal or electroluminescent panel, and which can accommodate increased amounts of display information.
To achieve the above-described object, the present invention includes a matrix type display comprising a flat panel display element. Driving systems including a plurality of pairs of light-emitting elements and light-receiving elements are disposed around the display element for driving a matrix of display elements in response to a light-reception signal generated by each of the light-receiving elements, based on light from each of the respective light-emitting elements generated in accordance with an image signal. Each of the plurality of pairs of light-emitting elements and light-receiving elements form signals transmission paths.
According to one embodiment of the present invention, the wavelength of the light emitted by the light-emitted element of one of each pair of adjacent signal transmission paths is different from the wavelength of the light emitted by the light-emitting element of the other signal transmission path. This prevents mutual optical interference between the pair of adjacent signal transmission paths to allow the matrix of display elements to be optically driven.
Also according another embodiment of the present invention, a matrix type display of the type described in the preceding two paragraphs is provided with an optical interference preventing member between the light-emitting element and light-receiving element of each of the signal transmission paths. This member allows the matrix of the display elements to be driven using optical communication while reliably preventing interference between each pair of adjacent signal transmission paths.